You get both electrochemical and electrodynamic machining. They are both used for machining very hard alloys. I think Rolls-Royce did a lot in the 1970's on turbine blades, and other stuff where they want to remove bits of material without annealing and altering the microstructure, or introducing stress damage.
I have done spark erosion (oaky, electrodynamic machining if yer posh). I was doing that on Ni-Ta single crystals which I wanted round for superconducting experiments, so I had the equivalent of a small lathe under paraffin, and the tool was a consumed bit of wire. The finish looks dull. Electrochemical machining is a different thing, but the end is much the same.
With electrochemical machining, the tool is not necessarily eroded, so it can be a complex shape. In theory you can get a smooth finish. Electropolishing is used for metallurgical samples, and can give you nice results, but it is cranky. Like electroplating, it can be affected by small changes in the bath chemistry. I am sure a quick google will probably throw up some of the old electroplating legends, like the old man who used to spit in the path, and his spit was just the right pH, or the guy who used to put in condensied milk. Probably both urban legends, but you get the idea.
These are the old JPEG images. I worked on DCT compression systems before JPEG, and had a tiny contribution to the freeware DCT code. When I saw the posting I immediatly suspected that the JPEG compression had been pushed up too high.
The original JPEG compression algorithm had Huffmann coding for the DCT variables, but it also had some fixed-length codes for the beginning and end of blocks. If you set your compression at about 10x then you can hardly see the difference with real images. bring it up to 15x and the changes are still modest. However, yank it much over about 22x, and the image will go to hell. The reason is the block handling codes meant that a JPEG image with no data at all - a flat tint - would only compress at about 64x, so at 22x compression these block handling codes are about 1/3 of your overall code. The fractional bit wastage you get with using Huffmannn coding instead of arithmetic coding mops up some of the rest as you are usig shorter Huffmann codes. The codes are also very regular, as about 1/3 of the code is not particularly random. The 1/3 figure also matches the 30% compression figures too, which isn't surprising.
Why didn't the original JPEG developers make a better job of this? Well, doing an experimental DCT compression used to take me hours or days when I was developing on a shared PDP-11, and there was always the worry that a dropped bit would lose your place in the code, and scramble the rest of the image. A little regular overhead was also useful for things like progressive JPEG control. I guess we all knew it was not as tight as things could have been, but it got the job done. We knew if you want to get 40x compression, then reducing your image to half size, and the compressing that by x10 will look better. Unfortunately, people who just drag a slider to get more compression don't always know that.
The right solution would be to use JPEG2000 which has a much smaller block overhead, and so fails much more gracefully at higher compressions.
There are famous cases of 3D shapes being trademarked, such as the Jif lemon, and the Cocoa-cola bottle. At one time, printer companies wanted to claim that the shape of their printer cartridges was a 3-D trademark and so could not be copied. However, 3D trademarks are a lot harder to establish than 2-D ones - some of them had to be around for 50 years - so I don't think this worked.
I believe there is a US sewing thread company has trademarked a peach (?) smell on its product. If course, we will not know whether this smell trademark stands up in law until another company wants to stick the same smell on their thread. Perhaps the vanilla smell of Play-Doh will provide the court case we need?
Amazing fact-oid: "...the signal from the distant star was more than a billion billion times weaker than a typical mobile phone handset!"
If a typical mobile phone handset was really the equivalent of a billion billion supernovas, then you could see why they don't let you use them on aircraft. Even one supernova stuck in your ear might cause cancer over long periods. Okay, I know the comparison is really between the signal from the supernova and the signal of a mobile phone somewhere within its operating range. Even then, the comparison is still pretty meaningless, as we are not interpreting data from the astronomical signal. Whatever...
It is hard to read someone else's code. However, show them the data and its structure and they can usually figure it out for themselves. If you want your data to live long, then stick the important bits in ASCII. You don't have to stick all your images into ASCII - perhaps just have the header tll you in text form that the data that follows is an image, has 3 bytes per pixel RGB, and the number of lines and pixels. This also allows you to write things like floating-point numbers in a way that does not depend on the machine precision and endian-ness. This, perhaps, is the computer equivalent of paper. You don't know what's on a bit of paper, but you can usually find out without any special tools, just by looking.
I don't know if media formatting is really part of the problem. My brother only exaggerates slightly when he says he has never deleted a file in 20 years, because his PC disk is always getting bigger. Your data should get copied at regular intervals if you want keep it alive. You will copy it even if you only do that when you upgrade your machine. If you don't, then magnetic media will slowly degrade, CD's may craze, punched cards may get used for shopping lists. If you still have the original text of your PhD on 1/4" tape, then it is probably not readable even if you could find a drive.
There is no reason why CRTs have to be as bulky as they are. The old flat Aitkien-Gabor monochrome tubes types wre less than 1 cm deep, and some were bright enough to be used as head up displays in aircraft cockpits pre-1970. There was an RCA flat colour tube that had red and green phosphors in either side of a transparent membrane, and the blue offset, so it suffered from parallax a bit. However, the right solution these days would be to resurrect the old Apple and Zebra tube beam landing technology. Sony had a go at this according to the patents, but I never remember seeing anything. Anyhow, modern electronics should cure all the targeting problems. Taking out the shadow mask could allow you to raise the resolution without the huge efficiency hit high-resolution shadow masks usually give you. As the tubes get flatter, then the volume goes down, so the total energy released in implosion goes down too. This means you can safely make the front screen thinner. And so on...
And yet, everyone tells us that CRT's are going to become extinct. They have the brightest and the best image, they have a unique variable resolution, and all the problems of portability are soluble, but nobody in the industry seems to want to bother, because CRTs simply aren't fashionable, and the makers are just sitting around, waiting to die. C'mon, folks, snap out of it! Gimme my flat monitor, already!
If you do research in a country, it is usual to apply for a patent in that country before you apply for any others. Often it is easier and more cost-effective, and a good way of establishing precedence. Now, Antarctica as an unusual international status, but it has been assigned one of the two letter patent codes, like 'US' for USA.
Maybe part of the solution to the intellectual property free-for-all from exploiting extremophiles might be to establish an Antarctic patent office to go with the letters.
This effect is a bit like superconductivity, and that is a bit easier to explain that, so I'll start with that...
Suppose you have a metal. This has positive nucleii, bound electrons which screen most of the nuclear charge, and conduction band electrons which can move thorughout the lattice, but also help to screen the nuclear charge. The whole thing is electrically neutral.
Suppose then you have some cloud of negative charge. This charge will repel the local electrons, and will attract the local nucleii. The nuclear lattice will bend a bit towards the center of the charge cloud, generating a local region of increased positive charge density that is screened out by the cloud of charge, and the other electrons.
Now, suppose this charge cloud moves. You have the same attractions and repulsions, but the nucleii have more mass per unit charge than the electrons in the cloud, so they will take a bit of time to react. The induced positive charge region will then lag behind the negative cloud, and will tend to drag it back. If you had a second negative cloud following some way behind the first one, it might be attracted towards this positive region.
If you had two conduction band electrons with long deBroglie wavelengths, with the same sorts of velocities and at the right distance apart, then you can get this sort of action. Over a limited range, you can get electrons to apparently attract each other, via electron-phonon iteraction.
This pairing up of electrons is pretty weak. If this was the only thing holding them together then you would not get superconductivity in ordinary materials above a few millikelvin. However, one they start organizing like that, then they can all tend towards a lowest energy state, where they are all moving like a single enormous particle, with a wavelength that is so much larger than most of the usual things that scatter electrons. A more electrons join this single state, an energy gap opens up betweeen the electrons that are in the state, and the ones that aren't, and it becomes more energetically tempting for other electrons to go with the flow. This energy gap stabilizes the superelectron state, and lets superconductivity happen at kelvin rather than millikelvin.
We have lots of particles giving off heat, but it isn't solidification. We don't have electrons standing shoulder to shoulder like soldiers. One superelectron's wave will significantly overlap hundreds or thousands of other superelectrons. If they had rigid orientations, then a supercurrent could not flow down a wire that got thinner, any more than your cheese with holes in it could flow down a funnel. Also, the electron-phonon coupling only binds if the electrons move. So, forget marching soldiers, unless you have soldiers that can see what is happening a hundred ranks ahead, and automatically calculate a path that will give zero jostling with their neighbours. It is not really a state that exist in the macroscopic world, but you can sort of guess what it might be like: everyone been cool and mellow and getting along with their neighbour, until one guy borrows the lawnmower without asking, or drinks the last beer in the fridge, and then it all suddenly collapses.
Okay, now if I get the article, you can get the same sort of thing with holes in a superfluid. The helium atoms can form a similar cooperating superfluid. The forces that balance to keep the atoms flowing in a coordianted fashion are different, but the principle is the same. If the particules are moving, and enough of their fields overlap, then there will be a lowest energy state, and one enough of them have discovered it, and particles can find it faster than random thermal fluctions can chuck them out, then everhting moves smoothly.
Helium atoms as lots of little round fuzzy things. Normally they overlap with lots of their neighbours. As you squish two of them together, the repulsive nuclear forces starts to rise sharply. The strong repulsive forces from the nearest neighbours will be bigger than the others, and wil
I would rather have a power connection than the internet connection. Usualy, there is plenty I want to do on a laptop, without getting an internet connection, and all the sysadmin fun and games that can involve. Sometimes I have almost flattened my laptop batteries waiting for the plane, just cleaning up my files and doing those jobs that you never get around to if there is anything else to do.
PS. The folding tray may stop your todger from doing a Hindenberg, but the little magnetic catch may zorsch your hard disc.
Scale is important. Turbulence happens more readily at large scales. Viscous drag is more significant at smaller scales. Gravity is more significant at larger scales. A very small insect is effectively rowing through the air, using most if its effort to propel itself along. An aircraft spends most of its effort creating lift - and drag, because the two always go together - to keep itself up. So, we're not going to have 747's with butterfly-shaped wings flitting from building to building. Which is a shame....
I used to do colour calibration stuff for Canon, and have measured printers and monitors in Tokyo and the UK. This isn't a definative answer, but maybe it will do for now.
The early CIE eye tristimulus models (the figures for spectral sensitivities of the eye's red, green, and blue detectors used in the CIE standard colour spaces) are still based on a very small sample of people. I beleve the first standards were based on only 17 people, all white, male Europeans. Even now, I think most standards are based on a sample of a little over four hundred people.
Why? Well, you cannot easily measure the tristimulus directly, so you have to get each of your subjects to match a lot of colours to characterise their eye's sensitivity over the whole spectrum. Then each person has a different yellow spot on their eye - the size and the density can vary quite a bit - so there is a fair amount of natural scatter. The case for natural tetrachromats claims the women's eye red response is bimodal, but when you see the tristimulus functions plotted out, it is really hard to see the evidence for it.
We do not have to rely on western figures. The Japanese had independently worked on colour science. The Ishihara who did the eye test patterns (he hand-painted the first ones using watercolours) did some measurements. But, again the populations measured were fairly small.
On the other hand, we know that the ability to remember and perceive colours is greatly affected by experience, and even the words used to describe colours. Tests on Bornean tribesmen that had separate words for yellowish-green (Wor) and bluish-green (Nol) were relatively better at remembering and distinguishing contrasts between these two colours then some other pairs of colours that the rest of us would find more easy. Now Japanese uses 'akai' for bright red paint, but also for skin colour (usually in connection with emotions), and brown shoe colour. Brown is usually 'chairo', which is 'tea-colour' but they also use 'kitsune-iro' (fox color) and 'tsuchi-iro' (earth-colour). If we are familiar with tomato red, brown, ochre, and brick red, we are bound to respond to colours and colour contrasts differently, but this does not mean we see them differently.
So, are Eastern and Western eyes different? The figures we have would suggest that you would not be able to identify the race of a person by their eye response - we are much more alike then we are different. If we measured a few tens of thousands of people, we might be able to drag some systematic difference out of the noise. But I don't think we could tell whether it was a genetic difference of a cultural difference, even then.
The pink cast on the DVD is much bigger than these differences. It's clearly an error. The suppliers ought to have offered a replacement DVD. Next time, they might. Give 'em hell, fellas, gambatte kudasai!
It's a nice idea. Not enough water comes from the oceans to the air in many parts of the world. The air a few meters above the sea has a potential of a few kilovolts when the waves have white caps. People have theorized that this stops a lot of mass and momentum transfer between the sea and the
air. This is the first mechanical solution I have heard about.
But there are bugs like Legionnaire's disease that like sprays of warm, damp air. Expect the unexpected, folks...
At one time I did patents for Canon. That was when they were one behind IBM in the world. One of the things I often had to explain was what a patent is actually good for.
Big companies and little companies have different rules. Big companies have defensive patenting strategies. 70% of Canon's patents were largely to stake out new intellectual territory. Most of these patents are never used as individuals - the smallest unit of patents for these agreements is often the roomful, unless you are lucky enough to have one of the really key ones (and they are rare).
Small companies and individuals will rarely have enough clout to force a cross-licencing agreement with Intel. Often the best thing they can do with their invention is to get what legal protection they cheaply can, and then lie low, and not attract the attention of the big players. In which case sticking a notice of your invention on an indexed and cross-referenced database that anyone can search is the very last thing you want.
Don't be fooled by the costs of filing a patent. You have to pay to keep the things going, too. How deep are your pockets? Do you want to pay to maintain a badly drafted patent?
You should be able to protect your invention by a 'declaration of invention'. This is a sort of publishing, but it can be obscure as you like. That will at least reserve you the right to a free licence from anyone else who sucessfully files a subsequent patent to manufacture your invention in its present state.
Is your invention really obvious? Some people seem to think that a patent is an award for doping something really clever. Really clever bits of engineering or computing may be best protected by obscurity. A good patent is an award for doing something really obvious. Sony patented the Walkman - a battery cassette recorder but without a record head. Once you see one, you know how it works and why it is worth doing, and then the patent is really valuable to keep off the competition.
You might try using the copyright laws to protect your design. You can write your own copyright (though doing it in some way that lets you prove the date afterwards is obviously a good idea), and you can get 50 years protection, instead of only 17 from a patent.
Some of the big companies are going this way. The really smart option these days is to protect your idea using the trademark laws, which can cover 3-d objects such as the Coca-Cola bottle, or the Jif plastic lemon, and have even been used to cover a scent added to sewing thread. If you can make your printer cartridge a trademarked shape, then no-one will be able to make copies, and the protection on a used trademark never expires.
If, after all this, you still go for a patent, then try and find an agent who is skilled in the field to do the patent searches. There is much prior art that is never found in the digitally searchable archives. When I was trying to find prior art for a type of computer monitor, I could find no prior art on the database searches, but I happened to find an old book on colour TV technologies from the 1960s that listed the amazing lengths people went to to get around the RCA shadow mask patents, including my invention in every detail godammit, and several other variations that I thought too hopeless to be worth persuing.
There is another reason for getting someone else to do your search. It is very hard if you are proud of your idea, to to a good job of trying to knock it down: I know I always did a better job on other people's patents, try how I might.
Thanks. I was going to post a very similar message...
The numbers are easy enough to calculate, but nobody else bothered to post any calculations. However, a lot of people were convinced that thing was a hoax without any visible calculations. This doesn't mean it isn't a hoax, but it does make it a lot less likely. Doing it is a lot more classy than just posting a hoax, isn't it (he says hopefully, but not with any real conviction)...
And William of Occam is gonna be well pissed when he finds out what someone's been doing with his razor.
There are several posts on this theme. I have picked this one to reply to, but the same applies to the others.
The diagnosis that doctors do not want to use the database because they are arrogant has strange similarities with the problems of the doctor's diagnosis itself. You may know one or two people who seem to fit this argument well. Probably these people have left a lasting impression on you. You may have come across counterexamples where a doctor had his or her opinion corrected, and was grateful for it, but that would be what you would expect, so it was not memorable.
Okay, back to doctors. Many people who suffer from something like asthma, a largely non-fatal disease where the patient may treat themselves for most of their lives, find they may know more about their disease than their doctors. Nowdays, there is an enormous amount to know about how to fix a person if they go wrong. Indeed, it is almost provable that there is more information than you can store in a single person, for it must encompass all the possible interactions of all people with all environments. Yet, despite all this mushrooming of information, the local doctor is still tasked with curing people using their own skills.
It is known that people are not naturally good at judging odds. We might expect that a doctor would notice if they prescribed anti-wobbliness pills, and several of those patients' left leg turned green. But, apparently not. Some doctors would see many such cases, and dismiss each in turn as something unusual. Then they might read an article in 'The Lancet' describing five cases where greenness in the left leg followed a prescription of anti-wobbliness pills, and then they make the correction. Maybe, there are so many things that might be correlated with so many things, and so many patients, that any ability to spot corelations is so overloaded that the poor thing just shuts down altogether. So, doctors take shortcuts: they rely on other clinicians to do their correlations for them.
If this is so, then the database should be viewed as nothing new - it is a body of experience and diagnostic strategy, just as much as books and periodicals. It is no more censorious than a spelling checker. A medical world based on trained humans cannot have its software upgraded overnight, so don't expect any sudden changes. However, if patients can use the database, and doctors can see it making their job easier, then its day will surely come.
Me, I know I could never learn all the stuff you need to get through medical school. Serious respect is due to those that do. But, try using the database, eh?
Most of the junk in space is little bits that fell off rockets. If you launch a lot of rockets to go and catch the bits of junk that fell off the last lot of rockets, then you are likely to be back where you started. Or worse.
It would be fun to blast the junk from earth using lasers or ion beams, but there are lots of problems with this. Ion beams 'hosepipe' in the atmosphere, and the laser beams reflect off shiny metal. If you could get even little bits of stuff out of orbit, then the military would be seriously interested.
It would be nice to have some passive thing like a big sticky web, but space is so mind-bogglingly big, that anything big enough to stand a reasonable chance of catching anything would have to be so huge that it would take a lot of rockets to lift it, which gets us back to point one. It seems you need something active that can 'see' the debris and go to meet it.
The only thing left seems to be to use a satellite that has a very long life in space, and so can offset the risk of adding to the junk with its launch. Suppose you had a big solar furnace in space. Anything at the focus would evaporate. The stream of evaporating material could be used to provide thrust to change the orbit. It cold use this thrust to intercept the next bit of rubbish, which it would then burn to catch up with the one after that. The art would be to keep the mass of the satellite very low, so it could get a lot of navigation out of a little bit of consumed mass.
It wont go off and start lunching on the ISS, but, hey, you can't have everything...
The news article left out all the interesting engineering bits. If you read it, it just sounds like yet another bigger telescope, big deal, so they are always getting larger, yada yada.
I have ground an eight-inch mirror. If you rub two glass plates with carbo between in a random fashion, the grinding and polishing process naturally produces a spherical surface. We actually want a parabolic surface, but the difference on an f8 mirror of this size is about half a wavelength. You can do this parabolizing by the same back and fourth process, but by pressing down a bit harder on the end of the stroke, to remove more material from the centre of the plate on top. It's a wonderfully low tech process that gives a very accurate result.
Now, if you scale up the mirror, then things get harder. The errors in a larger mirror scale up, so you have to take off many wavelengths thickness,so people have to use interferometers and computer controlled polishing machines.
Adaptive optics made parabolization easier. If your mirror is made up of segments that are a bit smaller than my eight inch mirror, then the differences between a spherical element and a paraboloidal element are no longer worth worrying about.
When you get to the size of the OWL, the difference in a 10 cm tile between a spherical surface and a flat surface is hardly worth worrying about. You could use float glass if it came in stress-free 10cm squares. You can make accurate plastic elements that would do the job. If you can stamp out computer controlled mirror elements, then maing a mirror the size of a football field no longer seems so impossible.
The next big thing is to make the telescope track a celestial object. This thing is going to be about the size of the great pyramid, and the mirror has to stay in shape to a fraction of a wavelength. They reckon they can do it for a billion (10e9) euros. I remember (maybe wrongly) that the Mount Palomar telescope cost about 400 million dollars, back in the late twenties, early thirties.
I am not sure yet that the thing can be built for the price, but it is beginning to look like it might. Cor, juice!
Well, I first started programming, I used a card punch where you had 12 buttons, one for each row of holes, and you had to do the chords for each character. Anyone else remember these things?
Kids of today, don't know they're born, bwah, bwah, etc..
'It's almost exactly like that scene in the original Star Wars where R2D2 ran a movie of Princess Leia saying 'Help me Obi Wan.'
I'm afraid not. The image does not move and you can't walk very far around it. Where the reflected beam and the reference beam interfere, you get the same distribution of light you might get off the original 3-D object. However, the image only extends to the edge of the holographic plate. Wander around to the front of the car and it disappears. Go around to the other side of where the car ought to be, and it stays gone, because there is nothing solid bouncing the light back.
Is this a real bit of kit, and if so, why don't they show a photograph of it?
We used to play Quake after work. After about half an hour of viewing my offal from unusual angles, I used to quit, go home feeling slightly nauseous, and not want supper. When I spotted the pattern, I stopped Quaking, and I was OK. It was something to do with dipping and diving around a 3-D maze without your inner ear getting the swerves it was expecting, I guess. I am told that experienced Quakers play through this feeling and get over it, but I never did. Dasher gave me a bit of the same experience, whoops, 'scuse me...
However, it is a brilliant way of explaining how arithmetic coding of text works.
This is not a new thing. All these issues were thrashed out when punched paper roll player pianos were made.
The early player pianos were simple mechanisms. There was no loud and soft controls other than the pedals, so the only way of varying the intensity of the sound was by playing the notes more often. You could not repeat notes too quickly or the roll might tear along the dotted lines, so the players used an octave tremolo style that gave these performances a very distinctive sound. Plus, the machines used to live in bars, so the tuning was sometimes rough, and beer got spilled inside.
Forget them. The Ampico series B used to have 16 levels of force behind the hammers, with separate settings for the 'left hand' and 'right hand' (not individual key control, but not bad for the time). The speed of the hammers was recorded using the spark-gap timing techniques used for measuring bullet velocities, a spin-off from the armament industry for WW1. Stick a roll in one of these beasts, and close your eyes, and it's just like being at a performance. Even a CD player and hedphones has trouble sounding this good. The downside was they cost a few thousand pounds, which in its day would buy you a street of houses.
Recording was not fully automatic. People needed to exercise judgement over how to convert things like the key velocities into the 16 pressure settings. There were also some sequences of rapid notes that could not be reproduced accurately. However, they could play the roll and log the timings, and edit it until the timings got as close as possible to the original performance.
So, is it live? Well, back then they decided there was no risk of duff notes, and you don't have the actual performer present, so it was definately not live, but in some respects it was better. Same would be true today, I guess.
The Ginzberg-Landau original paper just assumed the electrons paired up, and then went on to show that this had some of the right features of superconductivity. It's a tempting idea - add two fermions spin and make a boson, then let them condense. Unfortunately, it's also cheating. The microscopic explanation of why electrons should seem to pair up came a few years later with the Bardeen Cooper Schreiffer paper, and the many papers that followed.
Imagine a discreet electron moving through a positive lattice. The positive lattice will be attracted towards the negative electron. If the electron was still, the lattice would move towards it locally, and screen its charge. Because the electron is moving, and the lattice has intertia, the positive induced charge will lag behind the electron. This will slow down the electron, and also might attract any following electron if it is traveling at roughly the same speed. This is often described as electron-phononon coupling, and is rather more complicated than that simple explanation would suggest, but there is a weak force that does tend to cause electrons to match their velocities provided they maintain a respectful distance.
If electron-phonon coupling was all there was, then metals would only superconduct at a few milliKelvin. However the electrons are moving so slowly, and their wavelengths are so long, that each electron wavefunction may overlap with many thousands of others. If some of the electrons go into some ordered state, then it becomes energetically more likely for the neighbours to fit in too, and all of a sudden you get an energy gap between the ordered (superelectron) state and the disordered eletron states. This energy gap is much larger than the individual pairing energies.
If you are going to get the same sort of coupling and condensation using gravitiational waves, then you are going to need to balance the gravitational force with some sort of other repulsive force with the right sort of range. You might find this sort of balance in a neutron star, but I don't see it happening in the lab. But maybe I'm missing something...
I remember a security feature on a large piece of hardware. It had a secret diode hidden under an IC to stop customers upgrading the system with their own cheapo memory. The only people it ever caught out were the engineers themselves. Once word got out that there was a hidden diode, ordinary customers would take the board out and lift up the chip to see if it was there on their machine. And then, having got so far, they cut out the diode and tried upgrading their own memory.
This was an extreme case, but in general, protection via obscurity can make you life very difficult, and when it is cracked, it unravels very fast, so it is no good for a big organization
What is obscure to one person will not necessarily be obsure to another. Suppose you have some small item like jewellry you want to hide in your house. Where do you put it. In the freezer compartment of the 'fridge? In a polythene bag in the toilet cistern? Naah - apparently thieves mostly know a top ten list of places that Ordinary People Think Are Really Cunning Places To Hide Stuff, and they go through them in the first minute. If there was more obscurity about, then people would become better at cracking it.
The same works with UNIX passowds. They are encrypted using a known algorithm. It is too slow to crack by brute force - encrypting all the password possibilities and comparing the results to the entries in the password file. However, if your target system is used by sloppy people, and you try a list of the more likely works such as 'password', 'root' 'christmas', there is a decent chance of getting a crack in a reasonable time.
If you want difficult passwords, then why not stick them through the encrypter twice? It seems like a good idea, but actually this has can make the encryption weaker (remember the Enigma machine that could code not character as itself?).
However, suppose the password string was passed into some fixed custom routine written by the system administrator that mapped simple strings onto obscure ones? The hacker would not start off knowing this, so they will have to run a decent number of trials on the actual machine in order to reverse engineer that algorithm. If they crack that, then there is still the regular encryption to crack too, so at worst things should not have got any weaker. However, you still have a fixed algorithm, and if your hacker can get hold of that and your password file, then things are no different - it is just like having a slightly bigger encryption algorithm. The hacker runs through the possibilities, and comes up with a crack just the same.
Okay, suppose you have an obscure scheme that changes all the time? Could you make it so the crack is bound to be out of date by the time it is finished? Nope - provided the hacker can get a snapshot of the decryption process and the password file at one time, they can find the original password, and because the sloppy users won't have changed their original password, so that will still work even through your new encryption scheme.
This argument goes on forever. It is a bit like trying to build a perpetual motion machine. It may seem possible if only you could get hold of some really powerful magnets, and avoid being kidnapped by govenment agents like the last guy. However, you can't catch Newton's 3rd napping on the job. And you can't beat a good encryption algorithm and a good set of passwords. Bit of a shame, really but There It Is.
Before I get old and frail, I might like to move to 1/6th gravity. I would not be likely to have children, and the cumulative doses of radiation would probably not have a great deal of effect on my lifespan. Balance that against the reduction in stress on my system from reduced g, I would probably live longer, and remain active longer. If I stayed out for long, I probably couldn't come back and re-adapt to full gravity again, so I would probably have to move out for good.
Most people seem to think of speech processing as an untrained computer understanding ordinary human speech complete with all the sub-verbal input such as gestures, pauses, and emphasis. This is an ambitious goal, but it is not everything. We do not expect a computer to read our ordinary handwriting off a piece of paper. So, why do we expect our computer to understand what we say straight away?
Perhaps it is because speech interpretation is unfamiliar and underdeveloped. It is difficult to use a speech interface in a crowded office without annoying others. Most able-bodied people would chose to use a visual-tactile interface for most tasks. What gets used gets supported, and what gets supported gets used. However, this does not mean that speech interpretation is inherently flawed. For example...
Suppose you have found a telephone number in a directory. It is easy to read out the number; it is easy to listen to the number and press the buttons on the phone; but it is tricky to read and type the number. If your visual interface is already busy, then it can be a lot easier to use speech.
Suppose you are editing an image. You may be in a darkened room, and making subtle changes to the colors. You don't want to put menus and dialogues on your screen, because that will interfere with your sense of color balance, or block your view of your image. You can do a lot with simple commands like "make it greener" "make it bigger". One of the most useful things was to switch between "foregound" and "background". Remember the image viewer on Blade Runner?
I used to sit next to someone with RSI, who used to use MS-Word without the keyboard. He had a little thumbwheel mousy-thing which he could use with his arms folded for pointing and picking,but he could do everything on speech. He did take some time getting up to speed on the system, and he did have to train the computer, but I din't learn to use a keyboard overnight either.
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I have done spark erosion (oaky, electrodynamic machining if yer posh). I was doing that on Ni-Ta single crystals which I wanted round for superconducting experiments, so I had the equivalent of a small lathe under paraffin, and the tool was a consumed bit of wire. The finish looks dull. Electrochemical machining is a different thing, but the end is much the same.
With electrochemical machining, the tool is not necessarily eroded, so it can be a complex shape. In theory you can get a smooth finish. Electropolishing is used for metallurgical samples, and can give you nice results, but it is cranky. Like electroplating, it can be affected by small changes in the bath chemistry. I am sure a quick google will probably throw up some of the old electroplating legends, like the old man who used to spit in the path, and his spit was just the right pH, or the guy who used to put in condensied milk. Probably both urban legends, but you get the idea.
The original JPEG compression algorithm had Huffmann coding for the DCT variables, but it also had some fixed-length codes for the beginning and end of blocks. If you set your compression at about 10x then you can hardly see the difference with real images. bring it up to 15x and the changes are still modest. However, yank it much over about 22x, and the image will go to hell. The reason is the block handling codes meant that a JPEG image with no data at all - a flat tint - would only compress at about 64x, so at 22x compression these block handling codes are about 1/3 of your overall code. The fractional bit wastage you get with using Huffmannn coding instead of arithmetic coding mops up some of the rest as you are usig shorter Huffmann codes. The codes are also very regular, as about 1/3 of the code is not particularly random. The 1/3 figure also matches the 30% compression figures too, which isn't surprising.
Why didn't the original JPEG developers make a better job of this? Well, doing an experimental DCT compression used to take me hours or days when I was developing on a shared PDP-11, and there was always the worry that a dropped bit would lose your place in the code, and scramble the rest of the image. A little regular overhead was also useful for things like progressive JPEG control. I guess we all knew it was not as tight as things could have been, but it got the job done. We knew if you want to get 40x compression, then reducing your image to half size, and the compressing that by x10 will look better. Unfortunately, people who just drag a slider to get more compression don't always know that.
The right solution would be to use JPEG2000 which has a much smaller block overhead, and so fails much more gracefully at higher compressions.
I believe there is a US sewing thread company has trademarked a peach (?) smell on its product. If course, we will not know whether this smell trademark stands up in law until another company wants to stick the same smell on their thread. Perhaps the vanilla smell of Play-Doh will provide the court case we need?
If a typical mobile phone handset was really the equivalent of a billion billion supernovas, then you could see why they don't let you use them on aircraft. Even one supernova stuck in your ear might cause cancer over long periods. Okay, I know the comparison is really between the signal from the supernova and the signal of a mobile phone somewhere within its operating range. Even then, the comparison is still pretty meaningless, as we are not interpreting data from the astronomical signal. Whatever...
I don't know if media formatting is really part of the problem. My brother only exaggerates slightly when he says he has never deleted a file in 20 years, because his PC disk is always getting bigger. Your data should get copied at regular intervals if you want keep it alive. You will copy it even if you only do that when you upgrade your machine. If you don't, then magnetic media will slowly degrade, CD's may craze, punched cards may get used for shopping lists. If you still have the original text of your PhD on 1/4" tape, then it is probably not readable even if you could find a drive.
And yet, everyone tells us that CRT's are going to become extinct. They have the brightest and the best image, they have a unique variable resolution, and all the problems of portability are soluble, but nobody in the industry seems to want to bother, because CRTs simply aren't fashionable, and the makers are just sitting around, waiting to die. C'mon, folks, snap out of it! Gimme my flat monitor, already!
Maybe part of the solution to the intellectual property free-for-all from exploiting extremophiles might be to establish an Antarctic patent office to go with the letters.
Suppose you have a metal. This has positive nucleii, bound electrons which screen most of the nuclear charge, and conduction band electrons which can move thorughout the lattice, but also help to screen the nuclear charge. The whole thing is electrically neutral.
Suppose then you have some cloud of negative charge. This charge will repel the local electrons, and will attract the local nucleii. The nuclear lattice will bend a bit towards the center of the charge cloud, generating a local region of increased positive charge density that is screened out by the cloud of charge, and the other electrons.
Now, suppose this charge cloud moves. You have the same attractions and repulsions, but the nucleii have more mass per unit charge than the electrons in the cloud, so they will take a bit of time to react. The induced positive charge region will then lag behind the negative cloud, and will tend to drag it back. If you had a second negative cloud following some way behind the first one, it might be attracted towards this positive region.
If you had two conduction band electrons with long deBroglie wavelengths, with the same sorts of velocities and at the right distance apart, then you can get this sort of action. Over a limited range, you can get electrons to apparently attract each other, via electron-phonon iteraction.
This pairing up of electrons is pretty weak. If this was the only thing holding them together then you would not get superconductivity in ordinary materials above a few millikelvin. However, one they start organizing like that, then they can all tend towards a lowest energy state, where they are all moving like a single enormous particle, with a wavelength that is so much larger than most of the usual things that scatter electrons. A more electrons join this single state, an energy gap opens up betweeen the electrons that are in the state, and the ones that aren't, and it becomes more energetically tempting for other electrons to go with the flow. This energy gap stabilizes the superelectron state, and lets superconductivity happen at kelvin rather than millikelvin.
We have lots of particles giving off heat, but it isn't solidification. We don't have electrons standing shoulder to shoulder like soldiers. One superelectron's wave will significantly overlap hundreds or thousands of other superelectrons. If they had rigid orientations, then a supercurrent could not flow down a wire that got thinner, any more than your cheese with holes in it could flow down a funnel. Also, the electron-phonon coupling only binds if the electrons move. So, forget marching soldiers, unless you have soldiers that can see what is happening a hundred ranks ahead, and automatically calculate a path that will give zero jostling with their neighbours. It is not really a state that exist in the macroscopic world, but you can sort of guess what it might be like: everyone been cool and mellow and getting along with their neighbour, until one guy borrows the lawnmower without asking, or drinks the last beer in the fridge, and then it all suddenly collapses.
Okay, now if I get the article, you can get the same sort of thing with holes in a superfluid. The helium atoms can form a similar cooperating superfluid. The forces that balance to keep the atoms flowing in a coordianted fashion are different, but the principle is the same. If the particules are moving, and enough of their fields overlap, then there will be a lowest energy state, and one enough of them have discovered it, and particles can find it faster than random thermal fluctions can chuck them out, then everhting moves smoothly.
Helium atoms as lots of little round fuzzy things. Normally they overlap with lots of their neighbours. As you squish two of them together, the repulsive nuclear forces starts to rise sharply. The strong repulsive forces from the nearest neighbours will be bigger than the others, and wil
PS. The folding tray may stop your todger from doing a Hindenberg, but the little magnetic catch may zorsch your hard disc.
Scale is important. Turbulence happens more readily at large scales. Viscous drag is more significant at smaller scales. Gravity is more significant at larger scales. A very small insect is effectively rowing through the air, using most if its effort to propel itself along. An aircraft spends most of its effort creating lift - and drag, because the two always go together - to keep itself up. So, we're not going to have 747's with butterfly-shaped wings flitting from building to building. Which is a shame....
The early CIE eye tristimulus models (the figures for spectral sensitivities of the eye's red, green, and blue detectors used in the CIE standard colour spaces) are still based on a very small sample of people. I beleve the first standards were based on only 17 people, all white, male Europeans. Even now, I think most standards are based on a sample of a little over four hundred people.
Why? Well, you cannot easily measure the tristimulus directly, so you have to get each of your subjects to match a lot of colours to characterise their eye's sensitivity over the whole spectrum. Then each person has a different yellow spot on their eye - the size and the density can vary quite a bit - so there is a fair amount of natural scatter. The case for natural tetrachromats claims the women's eye red response is bimodal, but when you see the tristimulus functions plotted out, it is really hard to see the evidence for it.
We do not have to rely on western figures. The Japanese had independently worked on colour science. The Ishihara who did the eye test patterns (he hand-painted the first ones using watercolours) did some measurements. But, again the populations measured were fairly small.
On the other hand, we know that the ability to remember and perceive colours is greatly affected by experience, and even the words used to describe colours. Tests on Bornean tribesmen that had separate words for yellowish-green (Wor) and bluish-green (Nol) were relatively better at remembering and distinguishing contrasts between these two colours then some other pairs of colours that the rest of us would find more easy. Now Japanese uses 'akai' for bright red paint, but also for skin colour (usually in connection with emotions), and brown shoe colour. Brown is usually 'chairo', which is 'tea-colour' but they also use 'kitsune-iro' (fox color) and 'tsuchi-iro' (earth-colour). If we are familiar with tomato red, brown, ochre, and brick red, we are bound to respond to colours and colour contrasts differently, but this does not mean we see them differently.
So, are Eastern and Western eyes different? The figures we have would suggest that you would not be able to identify the race of a person by their eye response - we are much more alike then we are different. If we measured a few tens of thousands of people, we might be able to drag some systematic difference out of the noise. But I don't think we could tell whether it was a genetic difference of a cultural difference, even then.
The pink cast on the DVD is much bigger than these differences. It's clearly an error. The suppliers ought to have offered a replacement DVD. Next time, they might. Give 'em hell, fellas, gambatte kudasai!
It's a nice idea. Not enough water comes from the oceans to the air in many parts of the world. The air a few meters above the sea has a potential of a few kilovolts when the waves have white caps. People have theorized that this stops a lot of mass and momentum transfer between the sea and the air. This is the first mechanical solution I have heard about. But there are bugs like Legionnaire's disease that like sprays of warm, damp air. Expect the unexpected, folks...
Big companies and little companies have different rules. Big companies have defensive patenting strategies. 70% of Canon's patents were largely to stake out new intellectual territory. Most of these patents are never used as individuals - the smallest unit of patents for these agreements is often the roomful, unless you are lucky enough to have one of the really key ones (and they are rare).
Small companies and individuals will rarely have enough clout to force a cross-licencing agreement with Intel. Often the best thing they can do with their invention is to get what legal protection they cheaply can, and then lie low, and not attract the attention of the big players. In which case sticking a notice of your invention on an indexed and cross-referenced database that anyone can search is the very last thing you want.
Don't be fooled by the costs of filing a patent. You have to pay to keep the things going, too. How deep are your pockets? Do you want to pay to maintain a badly drafted patent?
You should be able to protect your invention by a 'declaration of invention'. This is a sort of publishing, but it can be obscure as you like. That will at least reserve you the right to a free licence from anyone else who sucessfully files a subsequent patent to manufacture your invention in its present state.
Is your invention really obvious? Some people seem to think that a patent is an award for doping something really clever. Really clever bits of engineering or computing may be best protected by obscurity. A good patent is an award for doing something really obvious. Sony patented the Walkman - a battery cassette recorder but without a record head. Once you see one, you know how it works and why it is worth doing, and then the patent is really valuable to keep off the competition.
You might try using the copyright laws to protect your design. You can write your own copyright (though doing it in some way that lets you prove the date afterwards is obviously a good idea), and you can get 50 years protection, instead of only 17 from a patent.
Some of the big companies are going this way. The really smart option these days is to protect your idea using the trademark laws, which can cover 3-d objects such as the Coca-Cola bottle, or the Jif plastic lemon, and have even been used to cover a scent added to sewing thread. If you can make your printer cartridge a trademarked shape, then no-one will be able to make copies, and the protection on a used trademark never expires.
If, after all this, you still go for a patent, then try and find an agent who is skilled in the field to do the patent searches. There is much prior art that is never found in the digitally searchable archives. When I was trying to find prior art for a type of computer monitor, I could find no prior art on the database searches, but I happened to find an old book on colour TV technologies from the 1960s that listed the amazing lengths people went to to get around the RCA shadow mask patents, including my invention in every detail godammit, and several other variations that I thought too hopeless to be worth persuing.
There is another reason for getting someone else to do your search. It is very hard if you are proud of your idea, to to a good job of trying to knock it down: I know I always did a better job on other people's patents, try how I might.
Oh, and good luck...
The numbers are easy enough to calculate, but nobody else bothered to post any calculations. However, a lot of people were convinced that thing was a hoax without any visible calculations. This doesn't mean it isn't a hoax, but it does make it a lot less likely. Doing it is a lot more classy than just posting a hoax, isn't it (he says hopefully, but not with any real conviction)...
And William of Occam is gonna be well pissed when he finds out what someone's been doing with his razor.
The diagnosis that doctors do not want to use the database because they are arrogant has strange similarities with the problems of the doctor's diagnosis itself. You may know one or two people who seem to fit this argument well. Probably these people have left a lasting impression on you. You may have come across counterexamples where a doctor had his or her opinion corrected, and was grateful for it, but that would be what you would expect, so it was not memorable.
Okay, back to doctors. Many people who suffer from something like asthma, a largely non-fatal disease where the patient may treat themselves for most of their lives, find they may know more about their disease than their doctors. Nowdays, there is an enormous amount to know about how to fix a person if they go wrong. Indeed, it is almost provable that there is more information than you can store in a single person, for it must encompass all the possible interactions of all people with all environments. Yet, despite all this mushrooming of information, the local doctor is still tasked with curing people using their own skills.
It is known that people are not naturally good at judging odds. We might expect that a doctor would notice if they prescribed anti-wobbliness pills, and several of those patients' left leg turned green. But, apparently not. Some doctors would see many such cases, and dismiss each in turn as something unusual. Then they might read an article in 'The Lancet' describing five cases where greenness in the left leg followed a prescription of anti-wobbliness pills, and then they make the correction. Maybe, there are so many things that might be correlated with so many things, and so many patients, that any ability to spot corelations is so overloaded that the poor thing just shuts down altogether. So, doctors take shortcuts: they rely on other clinicians to do their correlations for them.
If this is so, then the database should be viewed as nothing new - it is a body of experience and diagnostic strategy, just as much as books and periodicals. It is no more censorious than a spelling checker. A medical world based on trained humans cannot have its software upgraded overnight, so don't expect any sudden changes. However, if patients can use the database, and doctors can see it making their job easier, then its day will surely come.
Me, I know I could never learn all the stuff you need to get through medical school. Serious respect is due to those that do. But, try using the database, eh?
It would be fun to blast the junk from earth using lasers or ion beams, but there are lots of problems with this. Ion beams 'hosepipe' in the atmosphere, and the laser beams reflect off shiny metal. If you could get even little bits of stuff out of orbit, then the military would be seriously interested.
It would be nice to have some passive thing like a big sticky web, but space is so mind-bogglingly big, that anything big enough to stand a reasonable chance of catching anything would have to be so huge that it would take a lot of rockets to lift it, which gets us back to point one. It seems you need something active that can 'see' the debris and go to meet it.
The only thing left seems to be to use a satellite that has a very long life in space, and so can offset the risk of adding to the junk with its launch. Suppose you had a big solar furnace in space. Anything at the focus would evaporate. The stream of evaporating material could be used to provide thrust to change the orbit. It cold use this thrust to intercept the next bit of rubbish, which it would then burn to catch up with the one after that. The art would be to keep the mass of the satellite very low, so it could get a lot of navigation out of a little bit of consumed mass.
It wont go off and start lunching on the ISS, but, hey, you can't have everything...
I have ground an eight-inch mirror. If you rub two glass plates with carbo between in a random fashion, the grinding and polishing process naturally produces a spherical surface. We actually want a parabolic surface, but the difference on an f8 mirror of this size is about half a wavelength. You can do this parabolizing by the same back and fourth process, but by pressing down a bit harder on the end of the stroke, to remove more material from the centre of the plate on top. It's a wonderfully low tech process that gives a very accurate result.
Now, if you scale up the mirror, then things get harder. The errors in a larger mirror scale up, so you have to take off many wavelengths thickness,so people have to use interferometers and computer controlled polishing machines.
Adaptive optics made parabolization easier. If your mirror is made up of segments that are a bit smaller than my eight inch mirror, then the differences between a spherical element and a paraboloidal element are no longer worth worrying about.
When you get to the size of the OWL, the difference in a 10 cm tile between a spherical surface and a flat surface is hardly worth worrying about. You could use float glass if it came in stress-free 10cm squares. You can make accurate plastic elements that would do the job. If you can stamp out computer controlled mirror elements, then maing a mirror the size of a football field no longer seems so impossible.
The next big thing is to make the telescope track a celestial object. This thing is going to be about the size of the great pyramid, and the mirror has to stay in shape to a fraction of a wavelength. They reckon they can do it for a billion (10e9) euros. I remember (maybe wrongly) that the Mount Palomar telescope cost about 400 million dollars, back in the late twenties, early thirties.
I am not sure yet that the thing can be built for the price, but it is beginning to look like it might. Cor, juice!
Kids of today, don't know they're born, bwah, bwah, etc..
I'm afraid not. The image does not move and you can't walk very far around it. Where the reflected beam and the reference beam interfere, you get the same distribution of light you might get off the original 3-D object. However, the image only extends to the edge of the holographic plate. Wander around to the front of the car and it disappears. Go around to the other side of where the car ought to be, and it stays gone, because there is nothing solid bouncing the light back.
Is this a real bit of kit, and if so, why don't they show a photograph of it?
However, it is a brilliant way of explaining how arithmetic coding of text works.
The early player pianos were simple mechanisms. There was no loud and soft controls other than the pedals, so the only way of varying the intensity of the sound was by playing the notes more often. You could not repeat notes too quickly or the roll might tear along the dotted lines, so the players used an octave tremolo style that gave these performances a very distinctive sound. Plus, the machines used to live in bars, so the tuning was sometimes rough, and beer got spilled inside.
Forget them. The Ampico series B used to have 16 levels of force behind the hammers, with separate settings for the 'left hand' and 'right hand' (not individual key control, but not bad for the time). The speed of the hammers was recorded using the spark-gap timing techniques used for measuring bullet velocities, a spin-off from the armament industry for WW1. Stick a roll in one of these beasts, and close your eyes, and it's just like being at a performance. Even a CD player and hedphones has trouble sounding this good. The downside was they cost a few thousand pounds, which in its day would buy you a street of houses.
Recording was not fully automatic. People needed to exercise judgement over how to convert things like the key velocities into the 16 pressure settings. There were also some sequences of rapid notes that could not be reproduced accurately. However, they could play the roll and log the timings, and edit it until the timings got as close as possible to the original performance.
So, is it live? Well, back then they decided there was no risk of duff notes, and you don't have the actual performer present, so it was definately not live, but in some respects it was better. Same would be true today, I guess.
Imagine a discreet electron moving through a positive lattice. The positive lattice will be attracted towards the negative electron. If the electron was still, the lattice would move towards it locally, and screen its charge. Because the electron is moving, and the lattice has intertia, the positive induced charge will lag behind the electron. This will slow down the electron, and also might attract any following electron if it is traveling at roughly the same speed. This is often described as electron-phononon coupling, and is rather more complicated than that simple explanation would suggest, but there is a weak force that does tend to cause electrons to match their velocities provided they maintain a respectful distance.
If electron-phonon coupling was all there was, then metals would only superconduct at a few milliKelvin. However the electrons are moving so slowly, and their wavelengths are so long, that each electron wavefunction may overlap with many thousands of others. If some of the electrons go into some ordered state, then it becomes energetically more likely for the neighbours to fit in too, and all of a sudden you get an energy gap between the ordered (superelectron) state and the disordered eletron states. This energy gap is much larger than the individual pairing energies.
If you are going to get the same sort of coupling and condensation using gravitiational waves, then you are going to need to balance the gravitational force with some sort of other repulsive force with the right sort of range. You might find this sort of balance in a neutron star, but I don't see it happening in the lab. But maybe I'm missing something...
This was an extreme case, but in general, protection via obscurity can make you life very difficult, and when it is cracked, it unravels very fast, so it is no good for a big organization
What is obscure to one person will not necessarily be obsure to another. Suppose you have some small item like jewellry you want to hide in your house. Where do you put it. In the freezer compartment of the 'fridge? In a polythene bag in the toilet cistern? Naah - apparently thieves mostly know a top ten list of places that Ordinary People Think Are Really Cunning Places To Hide Stuff, and they go through them in the first minute. If there was more obscurity about, then people would become better at cracking it.
The same works with UNIX passowds. They are encrypted using a known algorithm. It is too slow to crack by brute force - encrypting all the password possibilities and comparing the results to the entries in the password file. However, if your target system is used by sloppy people, and you try a list of the more likely works such as 'password', 'root' 'christmas', there is a decent chance of getting a crack in a reasonable time.
If you want difficult passwords, then why not stick them through the encrypter twice? It seems like a good idea, but actually this has can make the encryption weaker (remember the Enigma machine that could code not character as itself?).
However, suppose the password string was passed into some fixed custom routine written by the system administrator that mapped simple strings onto obscure ones? The hacker would not start off knowing this, so they will have to run a decent number of trials on the actual machine in order to reverse engineer that algorithm. If they crack that, then there is still the regular encryption to crack too, so at worst things should not have got any weaker. However, you still have a fixed algorithm, and if your hacker can get hold of that and your password file, then things are no different - it is just like having a slightly bigger encryption algorithm. The hacker runs through the possibilities, and comes up with a crack just the same.
Okay, suppose you have an obscure scheme that changes all the time? Could you make it so the crack is bound to be out of date by the time it is finished? Nope - provided the hacker can get a snapshot of the decryption process and the password file at one time, they can find the original password, and because the sloppy users won't have changed their original password, so that will still work even through your new encryption scheme.
This argument goes on forever. It is a bit like trying to build a perpetual motion machine. It may seem possible if only you could get hold of some really powerful magnets, and avoid being kidnapped by govenment agents like the last guy. However, you can't catch Newton's 3rd napping on the job. And you can't beat a good encryption algorithm and a good set of passwords. Bit of a shame, really but There It Is.
Before I get old and frail, I might like to move to 1/6th gravity. I would not be likely to have children, and the cumulative doses of radiation would probably not have a great deal of effect on my lifespan. Balance that against the reduction in stress on my system from reduced g, I would probably live longer, and remain active longer. If I stayed out for long, I probably couldn't come back and re-adapt to full gravity again, so I would probably have to move out for good.
Perhaps it is because speech interpretation is unfamiliar and underdeveloped. It is difficult to use a speech interface in a crowded office without annoying others. Most able-bodied people would chose to use a visual-tactile interface for most tasks. What gets used gets supported, and what gets supported gets used. However, this does not mean that speech interpretation is inherently flawed. For example...